In "My New Pals" in the May 2003 Word Ways, Susan Thorpe exhibited a list of 459 five-letter palindromes not recorded in Palindromicon II (Jeff Grant and Dan Tilque, Word Ways Monograph Series 6, 2002). These were found on the Web using the search engine Google.
"New Five-Letter Palindromes,"
Word Ways: Vol. 38
, Article 17.
Available at: http://digitalcommons.butler.edu/wordways/vol38/iss1/17